Now Mr. Barr is a mold inspector and remediator who charges about $125 to test mold in people's homes. He took a $1,000 home-study course he found on the Internet and passed a multiple-choice exam, plus a quiz over the phone. He even has a mold-inspector badge, issued by a group called the Certified Mold Inspectors & Contractors Institute. "We did a lot of research and study," during the course, says Mr. Barr, who feels he is qualified to do mold cleanup. [underlining and color added for emphasis].

As individual homeowners try to get a grip on their mold problems, state attorneys general and consumer groups say they are seeing a stream of complaints about botched cleanup jobs done by inexperienced workers. The problem has gotten serious enough that several states are working on regulations and licensing requirements for mold-inspection and -remediation companies.

GOT MOLD?   If the moldy area in your home is less than 10 square feet you can usually clean it up yourself. Here are some tips on getting rid of the fuzzy stuff -- and for making sure it doesn't grow back.   • First, fix the leak or whatever is causing moisture. If you don't, the fungus is likely to grow back.   • Don gloves, goggles and a mask. If the mold is on a hard surface, like ceramic tile, scrub the area with detergent and water and dry completely.   • Remove any absorbent or porous materials that are moldy—such as ceiling tiles and carpet—in a sealed plastic bag to prevent spreading mold spores.   • Keep indoor moisture below 60% relative humidity to prevent mold from growing back.   • Run the bathroom fan or open the window when showering. Use exhaust fans or open windows whenever cooking or running the dishwasher.   • Vent appliances that produce moisture, such as clothes dryers, stoves and kerosene heaters to the outside where possible.     Sources: epa.gov, WSJ research

Currently, there are no federal or state regulations, and mold companies aren't required to be licensed or certified.

"My nail technician is more regulated" than mold cleaners, says Melinda Ballard, head of Policyholders of America, a nonprofit group in Austin, Texas. "There's something wrong with that." Ms. Ballard started the organization, which helps people file insurance claims, after winning a mold-related lawsuit against an insurer.

Such suits helped give rise to a flood of mold claims and to so-called mold remediation -- an industry that was virtually nonexistent a few years ago. Lured by the promise of fatter paychecks, workers with minimal training soon started billing themselves as mold remediators. There are now between 10,000 and 20,000 mold-removal companies in the country, according to the Indoor Air Quality Association, which offers a mold-cleanup training program.

Mold remediation can cost anywhere from several hundred dollars to more than $100,000 depending on the scope of the problem. And since almost every major insurer now excludes mold from standard policies, many consumers must pay out of their own pockets.

The proliferation of new companies has led to a number of horror stories. When Kase Velasco's kitchen sink started leaking, his insurer dispatched a company to clean up the water and black mold that had spread on the wall behind the sink. Mr. Velasco, his wife, and two children packed up and moved out of their Houston home and into a nearby apartment while the mold cleanup company took apart their house to eradicate the fungus.

GETTING HELP   If you need an expert to clean up mold in your home, here are some steps to help find a reliable one:   • Check a firm's complaint record with local consumer affairs agencies and Better Business Bureau.   • Ask for examples of removal experience and check references.   • To avoid conflicts of interest, don't hire the same company to do both the inspection and remediation.

Seven months, and about $22,000 in insurance money later, the family moved back. So did the mold. A round of testing showed mold levels were actually higher than when they left. He learned that the company hired to get rid of the mold had been in the roofing business just six months before.

"All they were was glorified demolition guys," says Mr. Velasco, a commercial-real-estate developer, who declined to name the company.

Mold Relief Inc., a nonprofit organization in Norman, Okla., that offers assistance to families affected by indoor mold, has received dozens of complaints from California to Oklahoma to Virginia about improper inspections or cleanup jobs. "I get calls from everywhere," says Elisa Larkin, executive director of Mold Relief. Companies come in to people's homes, she says, "and a week later there's mushrooms growing in the carpet."

Mold Restoration

Last month, Mold Restoration Inc., a mold-remediation company, agreed to pay upward of $800,000 for restitution to consumers in a settlement of a lawsuit brought two years go by then Texas Attorney General John Cornyn on behalf of half a dozen consumers. The suit alleged that the company left homeowners with unfinished restoration work meant to correct severe mold. An attorney for Mold Restoration says the company didn't admit any wrongdoing. Since June of 2002 the Attorney General's office has received nearly 200 other complaints against various mold-remediation companies.

At least two states -- Louisiana and Texas -- have enacted legislation that would require some form of licensing or registration for anyone involved with mold inspection, analysis or cleanup, though much of the details are still being worked out.

Several other states, and at least one federal lawmaker, have introduced bills that seek to research and establish standards regarding mold identification and remediation.

Part of the problem with trying to establish regulatory practices around mold is there are no standards for acceptable levels of mold inside a home. Molds are part of the natural environment and can be found practically everywhere. Different people have different sensitivities to molds. When testing is done, it usually just compares the levels and types of mold spores found inside the home with those on the outside.

If the moldy area is less than 10 square feet, you can usually clean it up yourself. If the moldy area is larger, or if you smell mold but can't see it, you should hire someone to do the cleanup. Experts advise that homeowners check with local consumer affairs agencies and the Better Business Bureau before engaging a testing or remediation company. Ask a company for examples of removal experience and check references. And avoid conflicts of interest by not hiring the same company to do both the inspection and remediation.